This invention relates generally to systems that communicate with units in vehicles for road user charging purposes and, more specifically, relates to anomaly detection for road user charging systems.
In road user charging systems, an on-board unit (OBU) is placed in each vehicle to be charged. The charging is based on, e.g., distance traveled, zone, time of travel, and the like. For instance, a goal for this type of system may be to managing traffic congestion by setting higher costs for travel on certain roads or in certain areas. Thus, roads or areas that are typically congested have a higher cost for travel. These systems also may include variable pricing based on travel during certain times of the day. That is, it is more expensive to travel during peak hours. These systems also provide taxes for use of the roads.
In many of these systems, the OBU keeps track of locations, times at those locations, and the like. At certain times, the OBU reports this data to a central location, called the “back office.” The back office then bills the user based, e.g., on a road use schedule.
Because these systems are becoming more widespread, abusers of the systems are also becoming more prevalent. For example, software is available to fake user location: information can be stored in the OBU indicating that the vehicle is located in a low cost zone, when actually the vehicle is located in a high cost zone. Additionally, the OBU may also be tampered with, switched off, or put into different vehicles.
Gantries typically serve as enforcement mechanisms. For example, a gantry observes a vehicle being in a high price zone but the vehicle claims to be in a low price zone at the observation time. As another example, a gantry uses automatic number plate recognition (ANPR) to determine that a license plate number viewed on a vehicle is different from a license place associated with the OBU for the vehicle.
While these techniques work for certain situations, gantries are an additional cost and a vehicle might travel paths with infrequent pathways through gantries. Further, a savvy abuser could determine where the gantries are and correct the data in an OBU prior to passing through a gantry, but then create incorrect data for those times when travel is not near a gantry. In these situations, gantries may have limited effect as enforcement mechanisms.
What is needed, therefore, are techniques for improving enforcement.